27 Jan
2006
27 Jan
'06
4:07 p.m.
On 1/27/2006 at 11:33 AM Joe R. wrote:
If we're talking about the Epson QX10, then there's no problem at all.
The later version of the board (which is what's in both my machines)
contaisn a 7220 (data sheet available), 16 RAMs, a bit of TTL and an
Epson gate array. But the technical manual shows schematics for that _and
for an earlier version_. That doesn't have the gate array, it has more
TTL and a character generator EPROM.
There must be some differences between the 'extra' TTL and the gate array
(IIRC there's a latch on a bus in one version that's not in the other),
but they are sufficiently similar that you could recreate a replacement
for the gate array based on the schematics in the manual. The only thing
you wouldn't have is the exact font of the character generator, but I am
sure you could create something that was readable.
A bigger problem in maintaing the QX10 are the 2 hybrids in the SMPSU
(but IIRC part-scheamtics without component values are in the manual) and
the 2 ASCIS on the floopy drive. And you'd have probllems swapping out
the complete drive as this is a 1/3rd height unit (not to mention the
fact that you'd want to keep the original one since it's an interesting
voice-coil unit).
-tony
Photograph it yes but a schematic is MUCH more
involved since all dies
have multiple layers. It's sort of like trying to make a schematic of a
multilayer circuit board when all you can see is the top layer.
Ditto that--and recall that we're talking here about an old graphics
controller; no crypto and (relatively) very old technology. I'd rather